Immune species-related differences

Kentolysin Compared to Heliantholysin. Stoichactis helianthus occurs in the Caribbean region whereas another species, Stoichactis kenti is distributed in the Indo-Pacific area. The latter produces a toxin, kentolysin, that is similar to, but not identical with heliantholysin (6). The amino acid compositions of the two polypeptides show a distinct resemblance but appear to differ significantly in number of residues of lysine, methionine, tyrosine and histidine. IgG from a rabbit immunized against heliantholysin neutralizes both heliantholysin and kentolysin, but neutralization of the homologous toxin is more efficient (Table III). It can be seen that in the concentrations used, the IgG failed to neutralize the related lytic peptides of Condylactis gigantea and Epiactis prolifera. 

In the whole field of immunity there is ample evidence of inborn biochemical individuality. Aside from acquired immunity there is natural immunity which is exhibited in species differences, race differences (in animals and in man), and in individual differences. Immunity is closely related to the individuality which has been... 

TXH. Kohne et al.24 devised Ti0H to remedy the compression of Tm values that is caused by criterion conditions and to correct for reduced NPH values that occur even for closely related species. Hall et al.39 interpret A TmH as a measure of median sequence diveigence between species. Smith et al.40 showed that TXH values are relatively constant even at different incubation temperatures. It is clearly useful to have such a criterion-independent measure of distance for comparisons made at different incubation temperatures. However, TXH is not immune to all the flaws of its constituent parts. Most importantly, the imprecision that is typical of NPH measurements gets incorporated into TXH. Also, TXH will be affected by kinetic effects just as is NPH. 

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